Marvelous things happen beneath the skin in the heat of the sweat bath.
The capillaries dilate permitting increased flow of blood to the skin in an
attempt to draw heat from the surface and disperse it inside the body. The
bather's skin becomes cherry red. The heart is pressed into a faster pace to
keep up with the additional demands for blood. Impurities in the liver,
kidneys, stomach, muscles, brain, and most other organs are flushed out by the
faster flow of juices. The skin and kidneys filter the wastes, excreting them
in sweat and urine.
Some
researchers claim that the rapid flexing of the heart and blood vessels in the
heat of the sweat bath is a healthy exercise that puts little more strain on the
heart than strolling on level ground. The increased capillary volume, they say,
keeps blood pressure normal. Other medical people, however, qualify their
commendations. One Finnish study observed that whereas blood pressure of
healthy persons remains approximately normal in a sweat bath, there occurs a
marked reduction of pressure in persons suffering from high blood pressure.
However, this effect is only transient, and the original condition returns soon
after the sweat bath.
American doctors commonly recommend that elderly people and persons with
heart problems should avoid sweat bathing. Finnish and German doctors feel
otherwise. Perhaps this difference of opinion arises from the fact that the
Germans and especially the Finns are more familiar with sweat
bathing.
While the surface temperature of the skin may rise as much as 10 degrees
C, inner temperatures increases up to 3 degrees C. This is the "fever" that
Hippocrates and generations of medical people after him sought, and is created
as one reclines in a sweat bath! Of course, it is unlikely that "every disease"
can be cured by fever, but it is common knowledge that many bacterial and viral
agents do not survive well at temperatures higher than normal body
temperatures. It is also possible that damaged cells repair themselves quicker
in fever conditions due to the increased metabolic rate. Recovery from illness
then comes easier and quicker.
The
inner temperature rise also affects the function of important endocrine glands,
the pituitary in particular. Located in the bottom center of the brain, the
pituitary is known as the master gland because its hormones regulates both
metabolism and the activity of other glands such as the thyroid, adrenal,
ovaries, and testes. Urged by the heat, the pituitary accelerates the body's
metabolism and affects the interplay of several of the body's hormones.
The
oxygen needs of the body increase by about 20%; so the lungs, another important
eliminator of body wastes, join in the body's quickened pace. (The lungs' rapid
exchange of carbon dioxide for oxygen is hindered in some sweat baths. In high
humidity, water condenses on the tiny alveoli where this exchange takes place
and breathing may be slightly more difficult. On the other hand, if the air is
too dry, as occurs in many American saunas, mucous membranes my become dry and
damaged.) Clogged respiratory passages are opened by heat, giving relief from
colds and other minor respiratory problems. Sweat bathing is not recommended
for those suffering from pneumonia or other acute respiratory
diseases.
When
the body is slowly cooled, the effects of heat are reversed - the heart calms,
sweat pores close, dilated blood vessels contract and body temperature returns
to normal. (The German Sauna Society recommends a warm foot bath to re-open
closed blood vessels.) On the other hand, abrupt cooling brought on by a plunge
into snow or icy water creates a more dramatic effect. For this reason, people
with weak constitutions should avoid rapid cooling. Vessels near the skin's
surface contract, but since the skin's metabolism returns to normal slower than
the circulatory system, wastes accumulate that are normally washed out by the
blood. Local vasodilators are then stimulated and blood rushes back to the
skin's surface. The heart continues to beat vigorously and you may experience
psychedelic flashes bouncing across your retina from the increased adrenal
activity - an unforgettable experience! The swift transition from hot to cold
stimulates the kidneys and usually creates the desire to
urinate.
The
body is 60% water by weight and any
pounds lost at this point will be promptly regained. (However, sweat baths have
an indirect effect on weight loss.) As you can imagine, the combination of
sweat bathing and cooling conditions the body, and a well-tuned body is more
resistant to colds, disease and infection. In cold weather, the warm glowing
feeling lingers for hours, while in hot climates, the body seems cooler than
before the sweat bath.
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